Comparing a Conservative Fluid Management Strategy to Usual Care in Participants after Cardiac Surgery

INTERVENTION: A protocol guided strategy for administering bolus fluid utilising stroke volume variation to limit fluid administration to those likely to be fluid responsive. Once the patient returns to the ICU following cardiac surgery, bedside staff ‐ nursing and medical ‐ will utilise a protocol to guide fluid administration. If the clinician suspects the patient to have a known or suspected inadequate cardiac output (i.e. the cardiac index is < 2.5L/min/m2; poor perfusion;poor urine output) and the stroke volume variation (SVV) is >13 then they will be instructed to administer a fluid bolus of 250mls of crystalloid or colloid as determined by the treating clinician. If the SVV is <13 then the treating clinician should consider using vasopressors to maintain or improve cardiac output. Type of vasopressor and dose will be determined by the treating clinician. The protocol will continue until the patient is desedated and extubated or they reach 24 hours post‐operative if still mechanically ventilated. Deviations from the protocol will be collected by the research nurses at each site. CONDITION: Cardiovascular disease PRIMARY OUTCOME: Intensive care unit length of stay from hospital database.. SECONDARY OUTCOME: Development of acute kidney injury using KDIGO criteria Disability free survival using WHODAS 2.0 Incidence of wound breakdown from review of medical records Incidence of wound infections from review of medical records Length of mechanical ventilation from review of medical records Mortality Quality of life using EQ5D Requirement for diuretic therapy from review of medical records Requirement for renal replacement therapy from review of medical records Requirement for vasopressor therapy from review of medical records INCLUSION CRITERIA: 1. Adult participants 16 years or older 2. Having elective cardiac surgery with cardiopulmonary bypass 3. Preoperative EUROSCORE II of 0.9 or greater